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Old 9th December 2011, 10:51 AM   #18861
PMA is offline PMA  Europe
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It might be, in some cases, for the reason of masking of non-harmonic digital artifacts by harmonic components related to music. This would also decrease the final resolution, which is also often preferred, believe or not.
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Old 9th December 2011, 11:47 AM   #18862
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Hi,

Quote:
Originally Posted by PMA View Post
I would rather say that they (tubes) overlap the source material by their inherent distortion pattern, which is pleasing for many listeners, but not for everyone.
Competently designed tube gear has distortion that is as low or lower than that of common speakers, for a given relative level, so if your contention is true it is equally applicable to speakers.

I would say given the long standing evidence on actual distortion audibility we may safely dismiss any charges of tubes being preferred for a given application due to them adding distortion in high fidelity applications.

Now Guitar and Bass Amplifiers are a different story. But remember, you can use Distorting Transistors as well, if not better to shape the sound of an Axe, depending on your style of music (Electro Harmonix Big Muff anyone?)

Ciao T
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Old 9th December 2011, 12:03 PM   #18863
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Do you have a set of FFT measurements to show here, for load about 10kohm (not 100kohm). Frankly speaking, I am more and more skeptical to verbal and written descriptions only, without support of trusted measurements.
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Old 9th December 2011, 02:02 PM   #18864
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Quote:
Originally Posted by ThorstenL View Post
Folks,



Seems at least on my browser the schematic does not display, here as attachment instead...

Ciao T
Looks like one of our old module schematics. I posted a stash of them from my archives that were not in Walt's history a few years ago.

EDIT - Yes that's one of John Cadigan's Model 40 Series, wonderful guy (passed away years ago) I learned a lot from him.
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Old 9th December 2011, 02:07 PM   #18865
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T

You mentioned doing a compound output stage with bipolars driven by complementary Fet (Mosfet?).

Previously I asked how many hidden common base/gate circuits are in an amplifier. I also showed the noise potential of power supply types.

Attached is the noise measurement results of the type of power supply I would expect in a power amplifier.

So if you use a complementary device off of the rails you have in effect a power supply noise follower.

I prefer to use a small split output coil transformer to provide a higher voltage drive rail and stay with followers that are driven by signals inside the cleaner (when designed correctly) core.

Please let me know what results you get.

ES
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Old 9th December 2011, 02:29 PM   #18866
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Ripple eater does a good job of cleaning this sort of thing up.
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Old 9th December 2011, 02:34 PM   #18867
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Quote:
Originally Posted by Bonsai View Post
Ripple eater does a good job of cleaning this sort of thing up.
Not on a power amp and the effectiveness declines as frequency increases.

BW shown is 5 Mhz. Spectrum not V/T
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Old 9th December 2011, 03:07 PM   #18868
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Quote:
Originally Posted by simon7000 View Post
T

You mentioned doing a compound output stage with bipolars driven by complementary Fet (Mosfet?).

Previously I asked how many hidden common base/gate circuits are in an amplifier. I also showed the noise potential of power supply types.

Attached is the noise measurement results of the type of power supply I would expect in a power amplifier.

So if you use a complementary device off of the rails you have in effect a power supply noise follower.

I prefer to use a small split output coil transformer to provide a higher voltage drive rail and stay with followers that are driven by signals inside the cleaner (when designed correctly) core.

Please let me know what results you get.

ES
Can you provide a circuit or reference? The description is a little to terse and I would like to better understand what you are describing.

The noise on your spectrum looks to be mostly power line related and less a function of the rectifier/cap combination. That is a really complicated problem to solve short of batteries.
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Old 9th December 2011, 03:15 PM   #18869
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Quote:
Originally Posted by PMA View Post
I would rather say that they (tubes) overlap the source material by their inherent distortion pattern, which is pleasing for many listeners, but not for everyone.
This view is quite common.
However:
Possibly there is more to sound quality than THD alone (as long as THD isn't too high).
Possibly tubes are inherently more linear then FETs and FETs are inherently more linear than BJTs.
Possibly my present CDP sounds so good and analogue-like despite of its' < 0.3% THD+Noise, not because of it.
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Old 9th December 2011, 03:18 PM   #18870
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Quote:
Originally Posted by PMA View Post
It might be, in some cases, for the reason of masking of non-harmonic digital artifacts by harmonic components related to music. This would also decrease the final resolution, which is also often preferred, believe or not.
Yes, in *theory*, that *might* work.
But I agree that lower resolution can sound 'better' sometimes, especially with inexperienced listeners.

jan
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